Such a time slot management method, main station and substation are already known in the art, e.g. from the published European patent application with publication number 0 544 975 A1. Therein, a time slot management system is described which includes a time division multiple access system with a main station connected to a plurality of substations by means of a tree like network. Substation identities are broadcasted in downstream information packets from the main station to the substations in order to thereby allow each one of the substations upon detection of its own substation identity to transfer upstream information in upstream information packets in predefined upstream timeslots. This time slot management system allocates the time slots in a flexible and dynamically way. The needed bandwidth to transmit upstream information is requested by the substations to the main station and the substations are informed by the main station of the allocated timeslots.
A feature of the described time slot management system is that the downstream information packets are including a predetermined number of blocks each of which include a header part and an information part. In order to reduce the overhead of the downstream information packets a first step is realized to distribute the stream of substation identities over the header parts of this predetermined number of blocks and a second step is realized to performe only one error check for this predetermined number of blocks and to distribute the error check information bits over the header parts of the predetermined number of blocks. In this way, the overhead of one information packet is a reduced number of bits.
It has to be remarked that in order to keep a maximum transfer capacity between the main station and the substations it is desirable to keep the number of bits of the overhead of the information pockets as low as possible.